There is no particular best gift. It all depends on the person, their interest, their needs. Throughout the year I try to pay attention to what my other half or my children pick up and show an interest in. But they know we can't get it at the time or it's just a 'want' item for themselves. Or I may hear them say, "Ah, I'll just wait on this" and they'll pick up something else. I pay attention to the novelty stuff they look at too for funny gifts.
For example, my son used to go to his friends house and play the drums. I never knew he could play, I thought they would just play around and make a bunch of noise. Then he showed me a video of him playing and it knocked my off my feet! I couldn't believe he had this talent. It was summer time and I knew we had to get him a drum set. Finally, when Christmas came the face he had was priceless when he opened the boxes. He loved his gift!
So just pay attention to what your loved ones look at or show interest in and you'll come up with the perfect gift for them.